Laminin is a glycoprotein found in the basement membrane around nerves. There is much current interest by neurobiologists in laminin since it stimulates the regeneration of nerves. The goal of this proposal is to study the mechanism of laminin-induced process outgrowth in cultured cells. The neuroblastoma x glioma cells (NG108-15) to be used in this study are a hybrid line which proliferates in culture, yet possesses many primary neuronal properties such as transmitter synthesis and synapse formation. The hypothesis to be tested here is that laminin binds to a receptor on the surface of cells, thereby inducing cytoskeletal changes that cause process outgrowth. The effect of laminin on the location and organization of cytoskeletal microfilaments and microtubules will be investigated using indirect immunofluorescence techniques and electron microsocopy. In addition, the drugs cytochalasin and vinblastine which inhibit the polymerization of cytoskeletal proteins will be used to probe the cells' response to laminin. Since the laminin molecule has separate domains which function either in attachment to substrates or in outgrowth of neurites, fragments of laminin believed to possess these discrete functions will also be tested and the response of the cytoskeleton evaluated as above. The results of the proposed study will provide information on the mechanism of laminin action and the mechanism of regeneration of nerve processes. Understanding better the interaction between laminin and neurons will be important for designing prostheses that enhance nerve outgrowth following injury and disease.